1. Technical Field
The present invention relates to a vehicle cabin exhauster. In particular, the present invention relates to a flap-type pressure relief valve.
2. Description of the Prior Art
U.S. Pat. No. 6,357,473 discloses a vehicle cabin exhauster including a vent plate that is fixed in the vehicle and that has vent openings. A movable vent flap is connected with the vent plate. When the air pressure inside the vehicle is less than the outside air pressure, the vent flap is in a closed condition overlying the vent plate and closing the vent openings, to block flow of outside air into the vehicle. When the pressure differential across the vent openings changes so that the air pressure inside the vehicle is greater than the outside air pressure, the vent flap moves to an open condition enabling flow of inside air out of the vehicle. The vent flap may be secured to the vent plate by adhesive, rivets, screws, clips, heat staking, or a separate bracket.
It is known to attach a vent flap of the type shown in U.S. Pat. No. 6,357,473 to a vent plate by bending the flap so that the edges of the flap can be fitted under projections on the vent plate. The edges of the flap are received under the projection, to retain the flap on the vent plate. Other portions of the flap fit around other projections on the vent plate to block lateral movement of the flap on the vent plate. The vent flap is made from Mylar.
U.S. Pat. No. 5,419,739 discloses a flap-type pressure relief valve. The flap is held onto a frame by a necked-down portion of the flap that extends through an opening in the frame.
U.S. Pat. No. 5,601,117 discloses a flap-type pressure relief valve. A pin on a frame extends through a hole in the flap. A retainer bar overlies the flap. The pin is cold-headed after the flap is inserted, to hold the retainer bar, and thereby the flap, in place.
In one known embodiment of the invention of U.S. Pat. No. 5,601,117, the flap is made from a thin, flexible rubber material. The pins are T-shaped posts having widened portions that are outside of and hold down the retainer bar. The retainer bar is needed to hold the flap in place on the housing, because the rubber material of the flap can tear off the T-posts.